My rocket does the shimmy. Then it dies.......

[-M-TheDoctor]

So I'm launching a probe to the Mun, should be an easy task, but for some reason, my rocket begins to violently twist and bend between the first and second stage. I've had this happen fairly often and have yet to figure out how to stop it from happening. Anyone experience this? What have you done to fix it? Thanks for the help! :D

Edited May 3, 2015 by [M]TheDoctor

[Kosmo-not]

Can you post a picture of the rocket? Are you using struts between the two stages?

*edit*

Having stability assist on can cause wobbling. Try turning it off and see if that helps. Sometimes, it's better to fly it manually for a bit.

[Starwhip]

First Question: Did you put struts?

Second Question: How many reaction wheels do you have? (Too many, probably... )

Third Question: Can you put up some screenshots?

[-M-TheDoctor]

Sorry, yes, screen shots help...

temp image upload

My first version of this rocket had only one reaction wheel, near the top. This version does have two, one at the top and one at the center, under the stack separator on the first stage. I'd never used two so I wanted to see if that fixed the issue. The wobble doesn't stat in earnest until around 40,000 m. Perhaps not using SAS after reaching orbit will help?

[Shpaget]

Dial down the gimbal on your lower stages, or turn the SAS off and drive manually.

[Gaugeforever]

In the last picture you are too far off prograde. If you want to turn, start sooner and only turn tot he edge of the prograde marker in the direction you want to go.

[Gaarst]

Add struts between your stages, this will make your rocket more rigid and will eventually prevent wobbling.

You should also consider deactivating the SAS wheels far away from the CoM

[-M-TheDoctor]

Thanks for the help guys! I deactivated the SAS after reaching orbit, and that stopped the wobble. I still couldn't do any moves with the first stage, but that was a non-issue.

image hosting 15mb

Thanks to all of you, the Foreseer Mun Probe has safely landed and is transmitting data from the surface of the Mun! :D

[Ulzgoroth]

Shutting off SAS to allow oscillations to damp out is something long rockets tend to need sometimes.

In the last picture you are too far off prograde. If you want to turn, start sooner and only turn tot he edge of the prograde marker in the direction you want to go.

At over 60 km up, being off prograde is probably not the problem. Not a lot of drag there.